Apparatus and methods for rendering animal materials and products produced thereby



3,398 APPARATUS AND METHODS FOR RENDERING ANIMAL MATERIALS US- 27 1968H. A. THEOBALD ET AL.

AND PRODUCTS THEREBY 4 Sheets-Sheet Filed Aug. ll, 1966 UVSQO WMUNL LUZAug. 27, 1968 H; A. THEOBALD ET A1. 3,398,677 APPARATUS AND METHODS FORRENDERING ANIMAL MATERIALS AND PRODUCTS THEREBY 4 Sheets-Sheet 2 FiledAug. 1l, 1966 Aug. 27, 1968 H, A, THEOBALD ET AL 3,398,677

APPARATUS AND METHODS FOR RENDERING ANIMAL MATERIALS AND PRODUCTSTHEREBY Filed Aug. ll, 1966 4 Sheets-Sheet 3 Aug. 27, 1968 H. A,THEOBALD ET Al. 3,398,677

APPARATUS AND METHODS FOR RENDERING ANIMAL MATERIALS AND PRODUCTSTHEREBY Filed Aug. 11, 1966 4 Sheets-Sheet 4 g 5 10W-Di Y .95 50 m 95 Iv/ 106' G O 106 51 l +yr 51 106 91100 00 41 54 g5 31 HZ 93 101 I N VENTORS HA an y A. mfom/. 4 :A L v/,v f, www

United States Patent 3,398,677 APPARATUS AND METHODS FOR RENDERINGANIMAL MATERIALS AND PRODUCTS PRO- DUCED THEREBY Harry A. Theobald, 36Stonebridge Road, Montclair, NJ. 07042, and Calvin C. Theobald, Kearny,NJ. (P.O. Box 68, Doctors Inlet, Fla. 32030) Continuation-impart ofapplication Ser. No. 303,384, Aug. 20, 1963. This application Aug. 11,1966, Ser. No. 571,920

4 Claims. (Cl. 100-37) ABSTRACT OF THE DISCLOSURE The invention isdirected to .apparatus and methods for rendering animal materialsincluding bones as part thereof, in a continuous operation from a sourceof supply by continuously:

(a) reducing said material to such size that at least 70% by Weightthereof is passable through .a ll/z" mesh screen and retainable on a 1A"mesh screen; then (b) heating said material in a range of about 140-215" F. and maintaining the water content thereof at a level of at least60% of that originally in said material and the fat content thereof at alevel of at least 35 of that originally in said material; then (c) whilein said temperature range and measuring at least 40% by weight of saidmaterial after said size reduction and containing fat measuring at least35% of that originally in said material and water measuring at least 60%and no greater than about 100% of that originally in said material,subjecting said material to increasing pressures in a continuouslyoper-ating screw press to separate fat and water therefrom until aresidue is obtained whose fat content is no greater than about by weightthereof on the dry basis, and separating said bones from the remainderof said residue.

This application is a continuationinpart of our copending application,Ser. No. 303,384, filed Aug. 20, 1963.

This invention relates to the art of rendering animal material whichamong others includes shop fat and bones, slaughter house waste, deadstock, poultry, oftal and the like. The animal material with which thisinvention is concerned does not include sh or other marine life andconsequently the term animal material Vas used in the presentdescription and claims does not include fish or other marine life. Inone of its more specific aspects the invention is directed to novelapparatus and methods for rendering animal material primarily for therecovery of fat and also commercial useful proteins and residuestherefrom. In another of its specific aspects the invention is directedto novel products produced by practicing the methods of this invention.Some of the unique products of this invention are the bone fractionsrecovered from the residues produced by practicing the methods of thisinvention, said bone fractions being substantially free ofextra-cellular fibrous and/or proteinacious material and surprisinglyfound to be useful for the production therefrom of gelatins of at leasttechnical grade in excellent yields.

The rendering of animal material especially for the recovery of fatstherefrom has been practiced for centuries. One of the very old methodswhich has been employed and is now employed to a very limited degree isknown to the art as the wet rendering process. It is a process whichconsists essentially in heating in water the raw animal material to berendered at atmospheric or above atmospheric pressures for extendedperiods thereby to liquefy and separate from the remainder of saidanimal ICC material practically all of the fat component originallycontained therein. Then the resultant mass is allowed to settlewhereupon the solids thereof settle in the aqueous medium and the moltenfat floats on the aqueous medium. The molten fat layer is removed fromthe solids containing aqueous layer. The solids containing aqueousl-ayer contains a residue yconsisting of water soluble and waterinsoluble components and is now subjected to evaporation thereby toremove the water and to leave behind a substantially dry, solid,substantially fat-free residue. This solid residue is then comminuted toappropriate size suitable for various use. This type of renderingprocess is not economically feasible today primarily because of the sizeof the plant required, the high cost of operation and low eiliciency.Another disadvantage of this process is that the rendered-bone fractionis not eminently suita-ble for the production of technical gelatintherefrom. This we believe is due to bones in the material so renderedhaving been subjected to high temperatures for long periods of time,thereby causing degradation or otherwise adversely aifecting theproteinacious and/or other components therein.

Another and more popular process, which for many years has foundacceptance in this art, is the so called conventional dry renderingprocess. This process in one form or another has been almost universallyadopted by the industry. A conventional dry rendering process consistsessentially of the following steps:

A raw animal material to be rendered is broken or cut up into pieces ofappropriate size. Then these pieces are charged into a cooker vesselwhich may be open t0 the atmosphere or may be of the so called closedtype. The pieces in said vessel are agitated, and over about a one hourperiod, heated to a temperature in excess of 250 F. When a cooker of theso called closed type is used, it is usual to maintain said vessel underslightly reduced pressure conditions while said material is being heatedtherein. In either case, when the cooker is open or closed, due to thehigh temperatures at which said pieces have been elevated over saidextended period, the hard bone pieces if any, originally present in saidmass, have been softened, the cells of said pieces have been rupturedwhereupon Vthe water and fat components originally combined therewithhave been released. Practically all, that is, more than of the watercomponent has been removed by vaporization from said mass and cooker andthe fat content is now in the molten condition therein. The cookervessel has a drain which is now opened -to permit molten fat to drainfrom said vessel and is recovered. In this step at least about 60% ormore of the the fat originally contained in said mass will drain offleaving behind in said cooker a residual mass having a moisture contentno greater than about 5% by weight, thereof, and a fat content nogreater than about 35-40%. The Water present apparently is water thatwas entrapped or otherwise held and prevented from being expelled andremoved from said mass during said cooking period, and the fat presentis apparently absorbed in or absorbed on the remainder of said residueand therefore did not escape from said vessel in said drainingoperation. Said residue ordinarily is treated in either one of twoconventional ways for recovering additional fat therefrom and to makethe residue more suitable for commercially economical purposes. One Wayemployed by plants of modest size is to charge said residue into a press4of the old and well known wine press type. Employed to a greater degreeand in plants of considerable size is an expeller such as the well knownAnderson expeller. Similar expellers and presses are widely employed inthe expression of oils from seeds and the like. They are characterizedby being machines of low capacity and high power requirements.

By employing such devices as the so called wine press and Andersonexpeller it is possible to squeeze fat out of said residue to produce amass containing about l to 15% fat. The other but more costly method ofextracting the fat from said residue is one of solvent extraction. Inthis, the hot residue is conveyed into agitated vessels and a batchthereof is charged therein for lling same to approximately 1/2 of itscapacity. The practical balance is made up with a suitable solvent suchas a low boiling parain hydrocarbon. The resultant mass is agitated fora short period of time and then allowed to rest after which theMiscella, Ia solution of the fat component in hydrocarbon solvent, ispumped off. Then the resultant residue is subjected to one or moreadditional extractions with such solvent. All of the solutions of fat inthe hydrocarbon solvent are collected. After the last extraction withhydrocarbon solvent, the resultant residual mass is agitated for aboutone hour while the vessel is heated under vacuum to vaporize oif theresidual solvent which is also collected leaving behind a substantiallysolvent free residue which is then purged with live steam and dried forl5 minutes. The resultant dried residue is then comminuted intoparticles making it useful as animal feed, etc. The collected solutionof fat in solvent is subjected to vacuum distillation whereby thesolvent is driven off, condensed and returned to storage for reuseleaving behind the extracted fat. Because the solvent extracts colorbodies in its use as an extractant herein and said color bodies remainbehind and dissolve in `the fat after the distillation of the solventtherefrom the fat usually is sub-standard, has poor color, andconsiderable fatty acid content which causes it to be of low grade.

This dry rendering process has a number of disadvantages besides thosehereinbefore set forth and `the following are some of them:

In the course of cooking some pyrolysis of the various components of theanimal material occurs due to high temperatures employed, ultimatelyresulting in the down grading of both the fat and residue recovered.This is evidenced by increased peroxide values, discoloration and higherfree fatty acid contents of the recovered fat and severe coagulation inthe proteinacious matter causing it to be somewhat indigestible foranimal feed. It also appears to be evidenced by the bone fraction of theresidue being practically useless for the commercial production oftechnical gelatin therefrom, which we believe is due to proteinaciousand/ or other matter in said bones having been degraded, denatured orotherwise adversely aifected due to the high temperatures used. It isfurther believed that a considerable amount of the not well understoodgrowth producing qualities is destroyed and therefore is not present inthe ultimate residues recovered, which is a real disadvantage if saidresidues are to be used as animal feed.

Said wet rendering and dry rendering processes have the furtherdisadvantage of creating industrial nuisances due to the odors createdby and emanating from said materials, in the course of processing, andpassing into the atmosphere.

Large rendering plants have the raw materials to be rendered deliveredto it by large pick up trucks. These trucks pick up said materials fromcustomers and then transport said materials therein to its renderingplant. The specific type of material picked up and delivered to theplant by the various trucks will vary greatly in content and specificcomposition. -For example, one or more trucks in any one day may pick upand .deliver shop fats and bones, with the bone content in one of thetrucks differing from that of another; one or more trucks may deliveronly oifal on that day; one or more trucks may deliver only fallenanimals and dead stock on that day; and one or more trucks may deliveronly slaughter house waste on that day, etc. As these individual trucks,carrying their respective loads, reach the plant, the ideal plant, whichhad not been achieved prior to this invention,

would permit the unloading of said trucks as they reached the plant,into a single hopper without regard to the particular material in theindividual truck, and from this hopper the material would be fed throughvarious processing units to render the material consisting of sizeableloads of significantly different compositions of significantly differentphysical characteristics and in non-bone solids, bone-solids, Water andfat contents.

The present invention has been made to overcome many, if not all, of the.deficiencies and disadvantages in the methods and apparatus of theprior art in the rendering of said animal materials and especially thosewhich are known to the art as inedible from which are produced the socalled humanly inedible products as determined by the U.S. governmentpure food and drug regulations.

An object of the present invention is to provide novel and uniquemethods and apparatus for the rendering of animal material andespecially for continuous rendering of animal material.

Another object of the present invention is the provision of novelmethods and apparatus for continuously rendering animal material wherebythe following advantages are obtainable:

(l) The capital investment of the plant including the necessaryequipment, some of which is novel, is cornpetitive.

(2) The efficiency of the plant is high and high yields of commerciallymarketable products are achieved at minmum cost.

(3) All materials normally to be processed by the industry areprocessable economically.

(4) Mild flavored fats similar to the fats in the cells, withoutappreciable increase of fatty acid, darkening of color or loss ofbleachability, are recovered.

(5) The residues recovered are rich in protein and have good growthproducing qualities.

(6) Wide range of capacity and work as satisfactory with small loads aswith large loads of materials.

(7) Bone fractions are produced which are substantially free ofextra-cellular iibrous and/or proteinacious material and furthercharacterized as being eminently suitable for the commercial productiontherefrom of gelatins of at least technical grade in excellent yieldsmeasuring about 15% at least dry weight thereof.

(8) High protein fractions are produced when said bone fractions areseparated from the residue, so that in this manner the commercial valueof high protein fractions plus the commercial value of the bonefractions far exceeds the commercial value of the unfractionatedresidues due primarily .to the commercial usefulness of said bonefractions for the economical production of said high grade gelatinstherefrom.

(9) Conservative in water requirements.

(10) The use of organic solvent is eliminated thereby eliminating costof solvent loss and recovery as well as danger of re and explosionsattendant to processes in which such solvents are employed.

Another object of this invention is to provide a novel and unique pressfor continuously pressing and recovering fat and useful residues fromthe animal materials to be rendered.

According to this invention, the raw materials collected from thevarious sources are charged into a hopper at the plant. Then in acontinuous manner, the materials in the hopper are fed to a pre-breakerwherein the materials are cut, broken up or otherwise converted intopieces of reduced size such that at least 70%, and preferably at leastby weight thereof is at least 1A" and no greater than about 11/2. Whilesaid raw animal materials may be reduced to pieces of very small size,the present invention does not require such fine reduction as requiredby some recently proposed processes. A salient and irnportantcharacteristic of this invention is that it is permissible to processsuch relatively large pieces.

According to this invention said yanimal material is reduced to suchsize that the resultant pieces representing at least 70% and preferablyat least 90% by weight thereof is passable through a 11/2 mesh screenand retainable on a 1A" mesh screen. In fact, by following the novelmethods of this invention, it is possible to process a load of shop fatsand bones in the continuous operation even when the proportion of bonesin said load measures at least or even as high as 50% or more by weightthereof. And even when such material is a charge-part of the continuousprocess, the reduced size of the pieces are such that at least 30% andpreferably at least 50% by weight of the bones are in the range of W-l.For certain purposes the material is reduced to such size that at least70% by lweight thereof is in the range of 1r"-l1/2" and at least 30% byweight thereof is in the range of 11-1". And, in some cases especiallywhen the said bone fractions are to be separated from the ultimateresidue obtained herein, the reduced particle size of said material issuch that at least 30%, and preferably at least 50% o-f thebonecomponent is in the range of lW-l" and preferably such that at least20% and preferably at least 30% by weight of the bone-component thereinis in the range of AMJ/4. Said material of reduced piece size iscontinuously discharged from said pre-breaker and continuously heated toa temperature of at least about 140 F. preferably at least 170 F., andno greater than about 215 F., and optimumly at about l902l5 F. Theheating of said pieces to said temperature under such conditions,including the residence time of said pieces being heated, is controlledso that at the end of said heating step the water content of said piecesis at least 60% and preferably at least 70% of that originally containedtherein as said pieces are discharged from said prebreaker, and the fatcontent thereof is at least 35% and preferably at least 40% of thatoriginally contained therein as said pieces are discharged from saidpre-breaker.

When the bone fraction is to be recovered from the residue obtainedherein from said material containing bones as part thereof to berendered, the residence time of said material in said temperature rangeis controlled depending upon the temperature employed so that less than10%, if any, of the ossein component in said bone pieces in said sizeranges is denatured so that about 90- 100% of the ossein componentremains in its undenatured condition so as to be available forconversion to gelatin measuring at least by weight of said bonecomponent in said size ranges.

And in any case, whatever the composition of the animal material to berendered, the material of reduced particle size and in said temperaturerange is prefenably screened and then charged into a novel press. Whenscreened some liquid, consisting of some molten fat and some wlater, isdrained oif, The so partially fat and water depleted material is chargedinto the novel press while still in said temperature range, and measuresat least 40% by weight of said material as it is discharged from thepre-breaker and has a fat content at least 35% of that in said materialas it is discharged from said pre-breaker or that originally therein anda water content at least 60% and no greater and preferably less than100% of that in said material as it discharged from said prebreaker or.in `said original material. Said material charged into said press isfurther preferably characterized by having a fat content of at least 15%by wei-ght thereof and a water4 content at least as great as said fatcontent. Said material charged into said press, which is a continuouslyoperating screw press, is while still in said temperature range,subjected to progressively increasing pressures either in one stage or aplurality of stages whereby fat and some water therein are expressedtherefrom and recovered and the resultant residue so produced isrecovered and has a fat content measuring no greater than and preferablyno greater than 10% by weight thereof on an anhydrous basis. While inmost cases lit is preferred that the fat content of the residue be nogreater than 10%, it may sometimes -be desirable that such fat contentbe above 10% :and between about 15-20% `when said residue is to be usedas an animal food component. Ordinarily said residue containing nogreater than said 10% fat content on the anhydrous basis, is thensubjected to drying and grinding to provide a comminuted product usefulas such as fertilizers and/or animal feeds. Because the pieces, reachingthe press and while therein have not been subjected to excessively hightemperatures for long periods of time and have not been subjected toexcessive quantities of water at elevated temperature, pyrolysis andconsequent degradation of the components therein, darkening, increase infatty acid content, and reduct-ion in bleachability have -beenminimized. The leaching out of water soluble proteins and other usefulWater-soluble factors has been reduced. By maintaining said material ofre- -duced size at temperatures not exceeding about 215 F. andcontrolling the residence time so that it is short, when the temperatureis in the range of about 200-215 F. when compared `with the residencetime when the ternperature is say -l80 F., excessive denaturing,degradation or otherwise adversely affecting the components of saidmaterial is prevented, and the resultant residues obtained therefromafter being subjected to the actionof said pness, with or withoutsubsequent grinding is fractionated to recover the lbone fractiontherefrom in conditions substantially free of extra-cellular and/orproteinacious components of said residue.

Certain specific `methods for practicing this invention as well as novelapparatus of this invention are herein set forth by 'way of illustrationand not li-mitation and are shown in the drawings by way ofIillustration and not limitation.

FIG. l is a flow sheet which diagrammratically shows novel apparatus forpracticing the present invention.

FIG. 2 is a side view oif a novel press for continuously pressingmaterial continuously fed thereto and illustrates a specific aspect ofthis invention.

FIG. 3 is an end view of the right side of FIG. 2 as shown on samedrawing.

FIG. 4 is an enlarged horizontal cross-sectional view taken on lineIV-IV of FIG. 2 in the direction of the arrows.

FIG. 5 is a vertical cross-sectional view taken on line V-V of FIG. 4 inthe direction of the arrows.

FIG. 6 is a vertical cross-sectional View taken on line VI-VI of FIG. 5in the ydirection of the arrows.

FIG. 7 is an enlarged fractional view showing the extreme open positionof the choke.

FIG. 8 is a view like FIG. 6, except that it shows the extreme closedposition ofthe choke.

As shown in the drawings, apparatus which may be employed -in thepractice of this invention comprises the novel combinations shown andinclude certain novel units as parts thereof. Referring to FIG. 1 thereis a weighing scale 10 on which animal material to be `rendered isweighed. The truck together `with its contents is weighed thereon andthen raw stock is dumped from the truck into a receiving and supplyhopper 11 at the receiving end thereof. Located in hopper 11 is a feed-screw 12 which by an appropriate drive continuously feeds said rawstock from said hopper 11 into the receiving end of a screw conveyor 13which by an appropriate drive continuously feeds said raw stock to andthrough its discharge port 14 and into the receiving end of anappropriately driven continuously operating pre-breaker 15. Thepre-breaker 15 serv-es to break up the raw stock into pieces of thedesired size. In this combination a pre-breaker, such as the well knownDukes Hogor may be employed. The prebreaker 15 is set so that the sizeof the pieces which are continuously discharged therefrom at thedischarge end are such als those hereto-fore defined.

The mass is continuously discharged from the prebreaker through itsdischarge port 16 and into the receiving end of a heater 17 in whichsaid mass is heated to a temperature in the range of about l40-2l5 F.preferably about 170-2l5 F. and optimumly about 190-2l5 F. and while atsaid elevated temperature, may be discharge-d through its discharge port18 and into the receiving end of a novel press 20. It is preferred thatthe pieces be heated to a tempenature which is not in excess of 215 F.and in some instances not in excess of about 200 F. but above 140 F.which also contributes to the efficiency and the economical aspects ofthe present invention. The heater 17 may be any one of a number ofdifferent types, and may be of the steam jacketed-cylinder type having aheated screw therein for continuously advancing and heating the materialfed thereto through said heater to the discharge end thereof, or it maybe an ordinary conveyor consisting of a cylinder, or trough, -and acontinuously operable feed screw, Worm, or drag, and into which livesteam may be admitted for raising the temperature of the pieces thereinto the elevated temperature in said temperature range. The trough orcylinder of heater 17 may or may not lhave perforations therein along apart or all of the length thereof for the passage of liquids from saidmaterial reaching a temperature range in the course of passing alongsaid trough or cylinder towards the discharge end thereof. Whenperforated, the liquid discharging therethrough is conveyed to adecanter tank 23 by conduit 49. Whatever type of heater 17 is employed,the mass is continuously fed through said heater 17, and then preferablyonto a screening means 21, covering a fat receiver and chute 22 whosedischarge end is connected to the decanter tank 23.

The screening means 21, diagrammatically shown therein, may be a singlescreen or appropriate area and mesh number, or it may be of themulti-deck type, consisting of a multiplicity of appropriate screens,arranged appropriately in a progressively increasing mesh number, in adownward direction. The latter is preferably employed. The screeningmeans 21 may be, but not limited to, any of the well known gyrating,oscillating, vibrating or rotary types, or some combination of these,and may be motivated in any convenient manner. Whatever screening means21 is employed, said pieces reaching same are moved thereon, and someliberated molten fat, some water and iines are separated therefrom, passthrough the screens, and flow through conduit 22 and into the decanter23. The oversize material from the individual screens -is charged intothe novel press. The rate of heating of the pieces of reduced size insaid heater 17 to a ternperature in said range throughout substantiallythe entire mass of said pieces, without releasing and evaporatingtherefrom an amount of water measuring more than about 40% of the wateroriginally contained in said raw material to be rendered and withoutreleasing: and removing therefrom an amount of fat measuring more thanabout 65% of that originally contained in said raw material to berendered, is controlled. Thus, by controlling the ternperature of theheater 17 and the residence time of the pieces of reduced size beingcontinuously fed through the heater 17 to the novel press 20, the massis elevated throughout to a temperature in said range and while in saidtemperature range is continuously fed into the receiving end of thepress 20, while still containing at least about 60% of the water and atleast about 35% of the fat originally contained in said raw animalmaterial to be rendered. The mass fed into the receiving end of saidpress is characterized by being in said temperature range so that noappreciable degradation of the components therein has occurred, also dueto controlling said temperature and residence time.

Instead of continuously discharging the mass from the pre-breaker 15into the heater 17, an alternate route may be employed. In saidalternate route the mass may be continuously discharged from pre-breaker15 through a discharge chute 25 :and into a pre-melt slurry tank 26containing a quantity of molten fatty material usually taken as recyclefrom decanter 23, preferably maintained at 200-2l5 F. The tank 26 has arotary blade mixer 28 therein which constantly mixes together the fatand mass continuously fed thereto whereby a mixture is being constantlyproduced therein. The mixture in tank 26 is continuously pumped orconveyed from tank 26 through conduit 30 or substitute means onto themeans 21 where as before the free molten fat, some water and some finesow through means 21 to a decanter 23 and pieces of lesser fat contentpass into the receiving end of the novel press 20. The nes and watersettle to bottom of tank 23 and the fat oats on top and is continuouslydrawn off through conduit 32 and is continuously pumped in part to tank26 and in part to a storage tank (not shown) for refining.

Whether the preferred or alternate route is employed, the mass which hasbeen conditioned is now continuously fed into said novel press 20wherein it is pressed thereby to express therefrom some water and mostof the fat contained therein, thereby to produce a residue which passesthrough a chute 33 and into the receiving end of a continuously drivenscrew conveyor 35. The fat, together with some lines and water, fallinto a pan 41 having a discharge chute 42, communicating with chute 22,and then pass to decanter 23. The water containing solubles and fineswhich settle in tanks 23 may be pumped as required through lines 43 and44 into heater 17 and/or tank 26 and/or onto the wet residue which isbeing continuously conveyed by the screw conveyor 35. Then the mass inthe conveyor 35 is discharged through chute 37 thereof and into thereceiving end of a dryer 40.

When all or part of said water containing solubles and solids isconveyed to one, two or all three of elements 17, 26 and 35, theproportion thereof delivered thereto may be varied by the use of volumeproportioning devices not shown.

The dryer 40 which has lifting flights is rotated to lift the Wetresidue fed therein and cause it to fall downward while being subjectedto a stream of hot air and is ultimately discharged in the substantiallydry state through chute 48 and may or may not be ground depending uponits fineness and intended ultimate use. The ground or unground dryresidue may be fractionated to separate same into two main fractions,one consisting essentially of fibrous and/ or proteinaceous material andthe other of pieces of polished bone extra-cellulary free of fibrousand/or -proteinaceous material.

In one of the specic aspects of this invention there is provided novelapparatus for continuously pressing the material fed thereto. Said novelapparatus comprises a screw press in combination with means forautomatically controlling the size of the discharge port thereof inresponse to pressure exerted by said material at the discharge end ofsaid press. More specifically said novel combination comprises a screwpress and preferably a multistage screw press in combination with achoke at the discharge annulus thereof together with means for movingsaid choke forwardly and rearwardly in said annulus thereby to reduceand enlarge the effective size of said annulus, with said means beingoperable in response to differences between the pressure exerted uponsaid choke by said material at said annulus and a substantially constantand predetermined pressure applied thereto and exerted thereon in adirection opposite to that exerted thereon by said material.

A specific embodiment of a novel press of this invention, shown by wayof illustration and not limitation, vis that shown in FIGS. 2-8 of thedrawings. The novel press shown consists essentially of a screw presswhich is of the continuous multi-stage type in combination with means atthe discharge annulus or part thereof, together with means for exertingconstant predetermined forces upon said means thereby constantly tendingto move said rst 9. means into said annulus or port thereby tending toreduce the effective size of said annulus or port.

As shown in the drawings there is a well known Renneburg continuousmulti-stage screw press, manufactured and sold by Edw. Renneburg & SonsCompany of Baltimore, Maryland which has been modified to provide anillustrative embodiment of a novel press of this invention. The press,shown in FIGS. 2 8 comprises a pair of longitudinally extending framesides 50 which are supported on vertically disposed supporting standardsor standions 51. Supported lby the frame side supports 50 along thelength thereof is a ca-ge 53. The cage 53 is in the form of a cylinderof closely spaced longitudi-nally extending slats 56 with longitudinallylextending openings 55 therebetween for the passage of fluids therethrough. The ca-ge 53 is in form of two like semi-cylindricallongitudinal sections coupled to each other, with the individual slatsof each maintained in position vby a plurality of like semi-circularrings 56 which also serve as reinforcing elements and elements forcoupling the cage 53 to the frame sides 50. One end of the cage 53 has afeed hopper 58 coupled thereto and in communication therewith for theadmission into said cage 53 of material to be pressed. A hollow drivetube 60 is located in said cage 53 and extends approximately the fulllength thereof, with its lon-gitudinal axis being coincident with thatof said cage 53 and with the outer periphery thereof being spaced fromthe interior of said cage 53. One end of said tube 60 terminates in ajournal extending through one side of said hopper 58 and is rotatablysupported in a bearing carried by a frame end 61. A conduit 62 issupported by the frame end 61 and is coupled with said journal having anopening therethrough yfor admission of steam or other fluid heatingmedium into said drive tube 60. The tube 60 has an interior closure 64nea-r one end thereof to prevent the escape of the heating fluid yfromthat end. The drive tube 60 has a plurality of, and as shown, fourcylindrical collars 65, 66, 67 and 68 secured thereto and spaced fromeach other along the length thereof. Said collars are of progressivelyincreased external diameter going in the normal direction of feeding,when said press is in operation. Four frustro :conical hollow elm-ents70, 71, 72 and 73 whose ends of smaller external diameter aresubstantially the same and whose ends of larger external diametercorrespond with the external diameter of the respective collars 65-68 towhich they are secured, are mounted on and locked to the tube 60. Thesmaller end of each of said elements 70-73 is located an appreciabledistance from the next preceding collar carried by said tube 60. Thatportion of the tube 60 in the hopper 58 and in that portion of the cageadjacent said hopper has secured thereto a screw flight 75 ofsubstantially constant pitch and outside diameter. This screw 75 isjoined at one end to a screw flight 77 constant outside diameter. Screwflights 78, 79 and 80 respectively, are secured to the frustro conicalelements 71, 72 and 73. Said flights 78, 79 and 80 are of differentinternal diameters but of the same external diameters as flights 75 and77.

According to this invention, the Renneburg press aforedescribed ismodified as follows to provide a novel press, an embodiment of which isshown in FIGS. 2-8:

Thelength of the cone 73 and flight 80 have been shortened and thelength of the collar 68 has been increased thereby to provide an annulusor port 81 of greater length. The length of the collar 68 is such thatit extends materially beyond the outer extremity of the cage 53. Aninternal drive collar 82, having an external flange 83 integraltherewith, has a portion thereof extending into the drive tube 60externally of the closure 64. The flange 83 is annular and its outsidecylindrical surface is in registry with the outside surface of collar 68and together said surfaces provide a bearing surface. The collar 82 issecured to the drive tube 60 by means of lock bolts 85 extending throughcollar 68 and flange 83. Secured to the Iframe sides 50 are holdingplates 87 which carry cylinder or ring and maintain said cylinder 90 inabutting position against the outer edge of cage 53 and the outer ring56 thereof. The ring 90 has a short internal cylindrical surface 91 inregistry with the interior surface of cage 53 at the outer extremitythereof, then has an interior surface 92 of gradually increasingdiameter over an appreciable length thereof thereby defining an internalfrustro conical portion and finally terminates in an internalcylindrical surface 93 of still lgreater length and of a diametercorresponding to the greatest diameter of said suryface 92. A castingsupport 95 is secured to the frame sides 50 and extends therebetween.The support 95 carries an internal bushing 96 through which extends oneend of a `drive shaft 97. Secured to the shaft 97 at either side of thebushing 96 and casting 95 are positioning collars 98. The shaft 97extends outwardly beyond the casting support 95 and has a bull gear 99secured thereto for driving said shaft 97. The other end of said shaft97 extends through the central opening in collar 82 and is operativelycoupled thereto by being shrunk-coupled therewith and/ or by linternalkey 100. Concentrically mounted on and rotatable with said shaft 97 is achoke 101 which includes a collar 102 keyed to the shaft 97 by key 103.Integral with said collar 102 is an annular flange 104 which in turn hasintegral therewith a cylinder 105 the outer surface of whose forwardfree end is in the form of an incline or cone 106. The outside diameterof cylinder 105 is slightly less than the inside diameter of cage 53.Integral with or otherwise secured to incline plane 106 are a pluralityof raised hard faced knives, ribs or bars 106 which are preferablynarrow and shallow and extend the full length of the incline plane. Theelements 106 extend along said inclined surface at an angle no greaterthan about 150 to a line formed intersecting said cone 106 with a planeat right angles to the axis of rotation thereof and in the embodimentshown said elements 106 are at right angles to that line. The thicknessof elements 106' is such that the effective end of choke 101 may befully inserted into the discharge opening 81 as shown in FIG. 8. Theinterior cylindrical surface of the part 105 of choke 101 bears on theoutside cylindrical surface of the flan-ge 83 and the outsidecylindrical surface of collar 64 which together provide a slide-bearingtherefor. The length and inclination of the suface 106 are substantiallythe same as the length and inclination of the surface 92; the length ofthe remainder of the outside surface of the part 105 is substantiallythe same as that of the surface 93; and the interior diameter of thering 90 is such and ring 90 is so disposed relative to the discharge endof cage 53 as shown in FIG. 4, that when choke 101 is in-its maximumretracted position as shown in F-IG. 4, the distances between surfaces92 and 106 and between 93 and the remainder of the outside surface ofpart 105 are substantially the same. The said maximum retractedposition, as shown in FIG. 4, and also shown in FIG. 5, shows that saidsurfaces 92 and 106 together define an inclined port communicating Withport 81` and port formed by the exterior surface of the remainder ofpart 106 together with surface 93, with the port 81 and said last portbeing of approximately the same width and with the incline porttherebetween being of a smaller widthwise dimension at the forward endthereof. Mounted on said collar 102 is a cylindrical bushing 107 havinga forward annular flange 108 integral therewith and bearing against theouter side of flange 104 and having a shorter rear annular flange 109. Athrust ring together with a thrust flange 111 integral therewith, isdisposed on the bushing 107, with the flange 111 bearing against theouter surface of flange 108 and the outer edge of ring 110 bealingagainst the inner surface of flange 109. A retaining ring is bolted orotherwise secured to colla-r 102 and faces against collar 102 and part109 to maintain the bushing 107 in position. Integral with said ring 110and flange 111 are a pair of diametrically disposed gusset plates 113having transverse openings therethrough. A pair of oppositely disposedlarge gusset plates 114 are secured to the frame sides 50.

A double acting hydraulic cylinder 116 connects each of the gussetplates 113 with the large gusset 114 opposite thereto. Each cylinder 116has a clevis 117 secured to the end of the chamber thereof and a clevis118 secured to the piston rod thereof. The clevis 117 is coupled to thegusset 114 by a clevis pin 120 and the clevis 118 is coupled to thegusset 117 by a clevis pin 121. Each of the hydraulic cylinders has apair of ports which are connected to hydraulic or air lines 125 and 126which are connected to a variable hydraulic or compressed air system formaintaining said cylinders 116 under pre-set pressure thereby constantlyto maintain the choking device under pre-set and predetermined constantpressure in a direction towards said cage 53. A cross channel 130 islocated below drive shaft 97, is secured to the frame sides 50 and has apair of spaced torque arm guides 132 secured thereto. Disposed in thespace between guides 132 is one end of a locking key 134 whose other endis secured to the thrust ring 110 to prevent rotation of ring 110 whilechoke 101 is rotated, but permits the entire, subassembly of choke 101,bushing 107 and thrust ring 110 to be actuated back and forth alongshaft 97. The bull gear 99 is driven by a pinion gear 142 of aconventional variable speed drive mechanism which is presettable todrive said shaft at any desired preset and predetermined speed.

The operation of the press is as follows:

The press 20 may be heated by feeding live steam into the hollow drivetube 60 through pipe 62, and said heating may be maintained throughoutthe continuous operation of the press to assist in maintaining at140-2l5 F. temperature of the mass continuously fed thereto afterpassing over screen 21. The main variable speed drive is energizedwhereby the pinion 142 drives bull gear 99 at a predetermined speed.Gear 99 in turn drives the shaft 97 together with the drive tube 60 andights and collars carried thereby and also the choking device 101. Thehydraulic or air system which also was pre-set and in operation appliesa predetermined uid pressure to cylinders 116 whereby the rotatingchoking device 101 is actuated towards the discharge annulus 81 and inthe absence of any material discharging through annulus 81, the inclinedend thereof carrying ribs 106' enters said annulus and substantiallycloses off said annulus 81 except for the space between the incline 106and the outer faces of ribs 106. The forward travel of the choke 101 islimited by the length of the maximum stroke of the cylinders 116. Themass at said elevated temperature is thus continuously fed into thehopper 58 and into the feed end of the cage 53 whereupon it is fedforwardly by fiight 75 into the first stage of the press where ight 77is located. Because of the progressive decreases in the volume of thepress at this stage, the mass is subjected to progressively higherpressures causing molten fat and some water to be extruded through slatopenings S5. Then said material is continuously forced from said firststage into the second stage. On its travel from the first to the secondstage, the pressure thereon is reduced and the material turns overthereby exposing new surfaces to the cage 53. Here again because of thedecrease in volume of the press where ight 78- is located at this secondstage, the pieces are again subjected to progressively increasedpressures, again causing molten fat and Water to be expressed therefromthrough slat openings 55. The volume of the press in this second stagebeing less than that of the first stage results in the exertion ofhigher maximum pressures in the second stage than those developed in thefirst stage. Then said material which has been subjected to highermaximum pressure in the second stage passes into the third stage and inthe course of this passage pressure thereon is released or greatlyreduced and the material turns over and is now subjected to still higherpressure in this third stage due to the decrease in volume of the pressin this stage. This is repeated in the last and fourth stage where thematerial is subjected to its greatest pressure and for the greatestresidence time whereby the maximum amounts of liquids are pressed outthrough the openings between slats 56. In all of these stages, moltenfat and some moisture as well as some fines are expelled from thematerial through the openings between slats 56 which expelled materialsare caught in the trough 41 which extends along the full length anddiameter of cage S3 and is located therebelow. A wet residue iscontinually extruded and discharged through opening 81 and into chute33.

When certain materials to be rendered, such as those containing highpercentages of fat or offal and the like, were to be pressed in thisapparatus in the absence of the application of choke 101, such materialswhen in the last stage of said press would not be subjected to thenecessary or desired high pressures and residence time therein.Consequently, insufficient amounts of the liquids would be removedtherefrom and therefore the wet residue passing out of discharge annulus81 would not be acceptable because of its excessive fat content, andtherefore such a press in the absence of the application of choke 101would 'be unsatisfactory for the purposes intended.

The rate of discharge of the wet residue out of the annulus S1 iscontrolled by the effective front end of the choke 101. The constantlyrotating choke 101 which is constantly maintained under a pre-set andpredetermined substantially constant pressure in a direction opposite tothe direction of feeding of said wet residue out of annulus 81, issubjected to pressure in the opposite direction by action of successiveincrements of the wet residue under pressure as they reach annulus 81.When the pressure exerted by said residue on the front end of saidrotating choke 101 exceeds the pressure applied to said rotating chokeby the cylinders 116, the inclined or front end of the rotating choke101 is to some extent moved rearwardly thereby to increase the effectivedischarge opening defined by the inner face of cage S3 at the outer endthereof and the incline 106 of the rotating choke 101. As thisdifferential in said pressures increases, the rotating choke 101 isforced rearwardly still further whereby the effective discharge openingsincrease proportionally. I'When the pressure exerted by said residue onsaid rotating choke 101 is less than that exerted on said rotating choke101 by cylinders 116, the choke moves forwardly to some extent towardscage 53 thereby to redue to some degree the effective annular openingbetween cage 53 and incline 106. As this differential in said pressuresdecreases, the rotating choke 101 is forced still lfurther forwardly inthat direction thereby to reduce still further the size of theeffectivepannulus between cage 53 and incline 106. In the aforesaidmanner, the action of the choke 101 serves to control the fiow andcharacter of the residue from the fourth and last stage of said press.It serves to -cause the material in said fourth stage to be subjected tothe maximum desired pressure and residence time at said pressure wherebythe max? imum amount of liquids are expressed therefrom through openingsbetween slats 56 at this stage thus producing a wet residue ofsufficiently low fat content as to be commercially acceptable.

The choke 101 in conjunction with the fourth stage of said press formswhat may be regarded as a chamber for compensating for variations in theeffectiveness of the previous stages due to the variations in thecompositions of the materials being pressed, wherein the materials areheld in residence in said chamber at maximum desired pressure forvarious periods, times depending upon the material in said chamber forthe aforesaid purposes.

The elements 106' serve to break such longer bones which are forced intothe discharge opening of the press and tend to or ldo clog that openingand further serve to act as a reaming device continuously to clean outand maintain the effective discharge opening in proper condition. Suchlong bones or the like which reach the discharge opening are broken upby the action of the rotating elements 106 and these elements actingtogether with the slats 56 at the discharge end of the press prevent theclogging of the discharge opening for unduly long periods of time.

In the practice of this invention, a batch-load or increment weighing1000 pounds was continuously processed in the manner heretoforedescribed and employing the apparatus described. This particular 1000pound increment consisted of a mixture of 500 pounds of shop fats and500 pounds of shop bones and of the following analysis, by weight, withthe solids being fat free solids:

Percent Fat 40.3 Solids 24.7 Water 35.0

After being subjected to the action of the pre-'breaker 15 andsubsequently heated to approximately 190 F. via either route thelresultant material at approximately 190 F. sliding off of the screen 21into the press 20 measures 705 pounds and the remainder 295 pounds whichwe term efuent #1 has the following average analysis by weight:

Percent Fat 71.0 Solids 8.0 Water 21.0

Said 705 pounds of material at approximately 190 F., which ywe termpre-rendered stock has the following average analysis by weight:

Percent Fat 27.5 Solids 31.6 Water 40.9

Percent Fat 49.6 Solids 16.4 Water 34.0

The press cake has the following average analysis by weight:

Percent Fat 5.15

I Solids 47.25 Water 47.60

When combined in decanter 23, etlluents #l and #2 weigh 650 -pounds andhave the following average analysis by weight:

Percent Fat 59.2 Solids 12.6 Wate-r 28.2

After the pressed cake extruded from the press 20 and measuring 350pounds was combined with the aqueous layer and lines from decanter 23and this mass 'was passed through the dryer 40, the resultant dried craxweighed 309 pounds and had an `average analysis by weight of:

Percent Fat l Solids 80 Water The dried crax, if required are thencomminuted to the `desired ines so that they are ready for bagging andshipment for use as animal feed or fertilizer.

In the foregoing procedure, the `residence time during which saidcomminuted material -was maintained at approximately 190 F. was suchthat practically none of the ossein in the bone component therein hadbeen denatu-red as evidenced by a technical grade gelatin yield of 15%.The dried crax -ground or unground, may if desired, be fractioned toseparate the bone particles from the extracellular proteinacious and-br-ous material. The bone fraction is substantially f-ree ofextra-cellulan proteinacious material, that is, it does not have suchproteinacious material adhering to the exterior surface thereof. Thisbone fraction may be size-classified and that in the range ofapproximately 3%; to approximately 1" in size is eminently suitable forthe production of high yields (16%) at least technical grade gelatintherefrom using conventional methods for the production of gelatin, asfor example, the method disclosed in Gelatin (Gelatin ManufacturersInstitute of America, Inc., 1962). The gelatins obtained from the novelbones of this invention are not only in good yields but yarecharacterized as having excellent Bloom Jelly strength as well as goodcolor and clarity.

Since certain changes may be made in carrying out the above process,land modifications effected in the apparatus for practicing theprinciple thereof, without departing from the scope of the invention, itis intended that all matter contained in the above description or shownin the accompanying drawings, shall be interpreted as illustrative andnot in a limiting sense.

It is lalso to be understood that the following claims are intended tocover all the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention, which as amatter of language might be said to fall therebetween.

We claim:

1. A method for rendering animal material including Ibones measuring atleast 10% by weight thereof comprising, in a continuous operation from asource of supply continuously:

(a) reducing said material to such size that at least 70% by weightthereof is in the range of -lW-lfl/z, and at least 20% by weight of thebones are in the range of 5A6"%"; then (b) heating said material in arange of about 170- 215 F. and maintaining the water content thereof ata level greater than 60% of that originally in said mate-rial and thefat content thereof at a level `greater than 35% of that originally insaid material;

(c) screening said material in said temperature range to drain off someof the fat and water therefrom; then (d) while in said temperature rangeand measuring at least 40% by weight of said material after said sizereduction and containing fat measuring at least 15% by weight thereofand at least 35% by weight of that originally in said material and watermeasuring at least Ias great as said fat and at least 60% and less than100% of that originally in said material, subjecting said partially fatand water depleted material to increasing pressures in a continuouslyoperating screw press to express fat and Water therefrom until a residueis obtained and discharged therefrom and has a fat content measuring nogreater than about 10% by weight on the dry basis; controlling theresidence time of said material in said temperature range whereby theweight of the ossein in said bones in said residue and in the range of5/16-%" is at least of that originally in said bones; drying andseparating said bones in said range -of 5/16-% from the matter in saidresidue exteriorly of said bones.

2. A method for continuously rendering animal material including bonesas part thereof comprising, in a continuous operation from a source ofsupply continuously: reducing said material to such size that at least70% by weight thereof is passable through a 11/2" mesh screen andretainable on a 1A mesh screen and the bone component thereof is reducedto such size that at least 30% by weight of said bone component is inthe size range of about 1/i"l"; then heating said material in a range ofabout 140-215 F. and maintaining the water content thereof at a level ofat least 60% of that originally in said material and the fat contentthereof at a level of at least 35% of that originally in said material;then while in said temperature range and measuring at least 40% byweight of said material after said size reduction and having a fatcontent measuring at least 15% by weight and water content at least asgreat as the fat content, and said fat measuring at least 35 of thatoriginally in said rnaterial and said water measuring at least 60% andno greater than about 100% 0f that originally in said material,subjecting said material to increasing pressures in a continuouslyoperating screw press to separate fat and water therefrom until aresidue is obtained whose fat content is no greater than about by weightthereof on the dry basis; controlling the residence time of saidmaterial in said temperature range whereby the weight of the osseincontent of said bone component in said residue and in said size range oflW-l" is at least 90% of that originally in said bone component;separating from the remainder of said residue the bone component thereinmeasuring 1:"l".

3. A method for continuously rendering animal material including bonesas part thereof comprising, in a continuous operation from a source ofsupply continuously: reducing said material to such size that at least70% by weight thereof is in the size range of about %-about lll/2"; andthe bone component thereof is reduced to such size that at least byweight thereof is in the size range of about IAN-1; then elevating thetemperature of said material in a range of about l40about 215 F. andmaintaining the water content thereof at greater than 60% of thatoriginally in said material and the fat content thereof at greater thanof that originally in said material; removing some liquid thereof; andsubjecting at least by weight of said partially liquid-depletedmaterial, while in said temperature range and having a fat contentmeasuring at least 15% by weight thereof and a water content at leastequal to said fat content and having a fat level measuring at least 35of that originally in said material and a water level measuring at least60% and no greater than about 100% of that originally in said material,to increasing pressures in a continuously operating screw press toexpress fat and water therefrom until a residue is obtained whose fatcontent is less than 20% by weight thereof on the dry basis; controllingthe residence time of said material in said temperature range wherebythe weight of the ossein content in said bone component in said residueand in said range of 1A-1 is at least 90% of that originally in saidbone component; separating said bone component from the remainder ofsaid residue.

4. A method for continuously rendering animal rhaterial including bonesas part thereof comprising in a continuous operation from a source ofsupply continuously:

reducing said material to such size that at least 70% by weight thereofis in pieces whose greatest dimension is no greater than about 11/2 andat least 30% by weight of the bones will pass through a 1 screen and beretained on a M1 screen; then heating said material to a temperature inthe range of about 175 215 F. and maintaining the fat therein at a levelgreater than 35 by weight of that originally in said material and thewater level therein at greater than 60% of that originally in saidmaterial, and feeding at least 40% of said material in said temperaturerange and having a fat content of at least 35 of that originally' insaid material of reduced size and a water content at least 60% and nogreater than of that originally in said material of reduced size, into acontinuously operating press, said press having a discharge opening atone end thereof and comprising a cage having a plurality of openings forthe passage of expressed fat and water therethrough, a continuouslyrotating screw continuously moving said material along the length ofsaid cage and exerting increasing pressures on said material therebyexpressing fat and water therefrom and through said openings in saidcage and thereby extruding continuously through said discharge openingsaid material in pressed condition and first means having a freeextremity, one end of said first means disposed in said dischargeopening for reducing the effective size of said discharge opening, theoutside surface of said end being inclined towards said free extremity,said incline surface being acted upon by pressure exerted thereon in onedirection by said pressed material in the course of its being extrudedthrough said discharge opening thereby tending to move said first meansin direction outwardly away from said discharge opening and second meansmaintaining said first means under pressure in a direction opposite tosaid first mentioned direction, whereby said first means is moved backand forth in said discharge opening in response to differences betweensaid pressures to increase and decrease the effective size thereofthereby to control the residence time of said material in said press andthe maximum pressure at which said material is subjected in said presswhereby said material in pressed condition passing through saiddischarge opening has a fat content of no more than 20% by weightthereof on an anhydrous basis, recovering said pressed material,controlling the residence time of said material while in saidtemperature range whereby the ossein content of said bones in saidrecovered pressed material and in the range of lW-l" is at least 90% ofthat originally in said bones, and separating said bones in the range ofabout 1,/4"-1" from the remainder of said pressed material.

References Cited UNITED STATES PATENTS 925,971 6/ 1909 Wheelwright260-412.6 1,766,033 6/ 1930 Meakin 23-280 2,340,009 1/ 1944 Meakin100-147 2,975,096 3/1961 Ginaven et al. 100-117 3,230,054 1/1966 Ling23-280 JAMES H. TAYMAN, JR., Primary Examiner.

